The Cyclotron/Radiochemistry Core provides all of the radionuclides, radioactive precursors, and approved PET radiopharmaceuticals for the research and clinical projects of this Program Grant. This includes production of fluorine-18 and carbon-11 precursors for Project 1, and routine deliveries of d-threo-[11C]methylphenidate, [11C]raclopride, (+) [11C]dihydrotetrabenazine, [15O]water and 5- [123i]iodobenzovesacicol for Projects 2-4. PET radionuclide production is done using a dedicated Cyclotron Corp. CS-30 cyclotron, outfitted with 10 cyclotron targets, 8 of which are located on a vertical beam ladder. Primary and secondary production targets are available for all radionuclides. All cyclotron targetry, mechanical, electrical and computer systems have been constructed in house; the Core provides all routine and emergency repairs for all of these systems, as well as for the cyclotron itself. Radiochemical research and routine production of PET radiopharmaceuticals is done in a well-equipped radiochemistry laboratory, which has the capability to delivery clinical doses of carbon- 11 radiopharmaceuticals in sequential fashion at less than 1 hour intervals. All syntheses are done remotely using apparatus designed, constructed and maintained by Core staff members. The Core provides established expertise in radiochemistry, radiation safety, quality control (including sterility and pyrogen testing), and documentation for regulatory approvals.